Odontomas in Cats: A Case Series

Introduction

Odontomas are rare, benign oral tumors reportedly found in dogs, cats, rodents, horses, oxen, primates, some species of fish, and humans. ¹ Classified as odontogenic tumors, they originate from developmental tissues of the teeth. As such, they are commonly diagnosed in younger patients and may or may not present with clinical signs depending on the age and species affected. Clinical signs include alveolar bone swelling and abnormal number of teeth (missing teeth or supernumerary teeth). ²

Odontomas are focal oral masses occurring in the maxilla and mandible composed of mixed odontogenic tissues and can present as compound, complex or rarely, mixed compound/complex. Compound odontomas have well-organized, highly differentiated tooth-like structures called denticles. ² Although they have morphological variations in comparison to normal teeth, denticles have histologically well-differentiated enamel, dentin, and pulp tissues with appropriate radio-opacity of the dental tissue elements. ² Complex odontomas are characterized by a disorganized arrangement of these same tissue elements, often resulting in a variably mineralized mass that lacks distinct denticles.^1–3 Regardless of type, odontomas can result in an expansile mass within the maxilla or mandible and can cause obstruction to tooth eruption, resulting in tooth impaction with a possible sequela of dentigerous cyst formation. Odontomas carry an excellent prognosis following surgical treatment via en bloc resection or more commonly, enucleation and curettage.^2,4,5

To the author's knowledge, this is the first publication describing odontomas in cats. Clinical, radiological, and histopathological findings, as well as treatment and outcomes for nine odontomas in eight cats are presented.

Materials and Methods

Eight client-owned feline patients with diagnosed odontomas were presented to various veterinary dentistry specialty practices between July 2013 and November 2023. Inclusion criteria for this study required the presence of a focal intraosseous mass of the maxilla or mandible with diagnostic imaging (intraoral radiographs and/or computed tomography [CT]) and histopathologic confirmation of odontoma.

Medical records from eight feline patients with nine odontomas were evaluated, and the data analyzed. Pertinent history and clinical signs were obtained primarily from information provided on the histopathology submission form, including photographs, for the eight cats included in this study. Additional medical records in two cases provided more detailed information. Signalment and patient data collected included patient age at time of odontoma diagnosis, breed, and sex/neutering status. Clinical history included presenting complaints, onset of signs, and duration of signs.

The documented clinical findings included tumor size, tumor location, dentition abnormalities associated with the tumor, and histopathologic diagnosis. Mass size was determined by the description in the medical record or histopathology submission form, or from the measurement taken during gross evaluation of the formalin-fixed lesion at the pathology laboratory. Location was categorized as either left- or right-sided, rostral or caudal, and maxilla versus mandible, with a classification of “extensive” if the lesion involved both rostral and caudal regions. Type of tooth or teeth was also designated if associated with the lesion.

Intraoral dental radiography and/or cone beam computed tomography (CBCT) studies were evaluated by a board-certified veterinary dentist (Diplomate, American Veterinary Dental College [AVDC]). Parameters evaluated included location of lesion, tooth displacement, evidence of tooth impaction, internal characterization of lesion (radiopaque, radiolucent, or mixed), and presence or absence of denticles.

Histopathologic features of feline odontomas included analysis of histopathological results by a board-certified veterinary pathologist. All samples were prepared by tissue fixation in a buffered formalin solution and decalcification of the samples with hydrochloric acid solution. Samples were then embedded in paraffin, sectioned in 5 µm slices, and stained with hematoxylin and eosin prior to histopathologic evaluation.

Treatment information, follow-up, and outcome were obtained from the medical record and communication with the veterinarian. Clinical resolution was defined as no evidence of clinical sign recurrence. Follow-up included either client update via telephone conversation or oral examination. Those patients who did not have a telephone update or did not return for recheck were deemed lost to follow-up.

Results

Signalment, History, and Clinical Signs

A retrospective study found eight feline patients with a total of nine odontomas confirmed by histopathology over a 10-year period, between July 2013 and November 2023 (Tables 1 and 2). There were four females and four males, all desexed at the time of presentation. Age at presentation ranged from 8 months to 12 years, with a mean age of 39 months and a median age of 14.5 months. Young patients predominated, with 75% of cases being less than or equal to 20 months old and four out of eight cases (50%) being less than or equal to 1 year old. All patients were mixed breeds, with six domestic shorthair cats and two domestic longhair cats.

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Table 1.

Signalment, Lesion Location, Treatment, and Follow-up of Odontomas in 8 Cats.

Case #	Age	Breed	Sex	Location	Size of lesion (mm)	Treatment	Histological margins	Follow-up
1	12 yr	DSH	FS	L mandible, caudal (309)	N/A	Enucleation	N/A	1-week phone update
				R mandible, caudal (409)
2	1 yr	DSH	MN	L maxilla, rostral (204)	12 × 11 × 4	En bloc resection	Incomplete margins	2-week exam recheck
3	7 yr 5 mo	DSH	FS	L mandible, rostral extensive (302-308)	N/A	Enucleation	N/A	Lost to follow-up
4	1 yr	DLH	MN	L maxilla, caudal (208)	8 × 5 × 4	En bloc resection	Complete excision	2-week exam recheck
5	1 yr 8 mo	DLH	FS	L mandible, caudal (308)	9 × 7 × 7	En bloc resection	Marginal excision	Lost to follow-up
6	10 mo	DSH	MN	L mandible, rostral extensive (301-307)	∼10 × 5	Enucleation	N/A	1 yr 8 mo recheck exam
7	8 mo	DSH	FS	L maxilla, caudal (207)	10 × 9 × 5	En bloc resection	Incomplete margins	1 yr 8 mo phone update
8	1 yr 6 mo	DSH	MN	R maxilla, caudal (108)	N/A	Enucleation	N/A	1 yr 3 mo recheck exam

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Table 2.

Clinical and Diagnostic Imaging Findings Associated With Odontomas in 8 Cats.

Case #	# of lesions	Alveolar bone swelling	Location	“Missing” teeth on physical exam	Tooth displacement or abnormalities	Tooth eruption abnormality	Radiolucency associated with odontoma	Compound or complex
1	2	No	L mandible, caudal (309)	___	308–309 and 408–409 tooth resorption	___	2 unilocular areas containing mineral opacities	Compound
			R mandible, caudal (409)
2	1	Yes	L maxilla, rostral (204)	___	___	Partially impacted 204	Radiolucent rim encircling denticles	Compound
3	1	Yes	L mandible, rostral extensive (302-308)	303, 304, 307	___	___	Radiolucent rim encircling odontoma	Compound
4	1	Yes	L maxilla, caudal (208)	___	___	___	___	Compound
5	1	Yes	L mandible, caudal (308)	___	308 - mesiolingual displacement	___	Radiolucent rim encircling denticles	Compound
6	1	Yes	L mandible, rostral extensive (301-307)	304	307- mesial displacement and root dilaceration	Impacted 304	Unilocular area containing denticles & 304 crown	Compound
7	1	Yes	L maxilla, caudal (207)	207	___	Impacted 207	___	Compound
8	1	Yes	R maxilla, caudal (108)	108	___	Impacted 108	Radiolucent rim encircling denticles	Compound

Only one of the eight patients (case # 1) had clinical symptoms which included a 2-week history of inappetence, and pain elicited when opening the mouth on initial oral examination that improved with a course of antibiotics. Case # 1 was unique when compared to the other cases, presenting as bilateral odontomas with no visible or palpable areas of bony swelling. However, the medical record did describe a small gingival enlargement near the apex of the left mandibular fourth premolar (308) and fluctuant swellings at both left and right mandibular first molar teeth (309, 409). The remaining seven cases, each with one lesion, were clinically asymptomatic and presented with an area of firm, nonpainful swelling covered by normal oral mucosa (Figure 1). On awake oral examination, teeth associated with the area of swelling were abnormal in six out of seven cases (85%). Specifically, four out of seven cases (57%) had an absent tooth/teeth associated with swelling, two out of seven cases (28.5%) had tooth displacement, and one out of seven cases (14%) had partial eruption. Location was primarily on the left side for seven out of nine lesions (77.8%). Maxillary versus mandibular location of the lesions was evenly distributed, with four lesions (44.4%) located in the maxilla and five lesions (55.6%) located in the mandible. Rostral versus caudal location was also similar, with two lesions in the caudal mandible, two lesions in the caudal maxilla, two lesions in the rostral mandible, one lesion in the rostral maxilla, one extensive lesion in the mandible, and one extensive lesion in the maxilla. When comparing largest width measurements, lesion size ranged from 8 to 12 mm. Size was not documented for three cases.

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Figure 1.

Odontoma in Case #8. A) Photograph Showing a Firm Swelling with Intact Gingiva is Noted in the Area of the “‘Missing”’ Right Maxillary Fourth Premolar Tooth (108). B) Intraoperative Photograph Showing Enucleation and Curettage of an Odontoma, Including Extraction of the Right Maxillary Third Premolar Tooth (107). C) Photograph of Denticles and Unerupted Tooth Removed from the Area of Swelling.

Diagnostic Imaging

Intraoral dental radiographs were available for all nine lesions. Radiographic findings are listed in Table 2. Among the seven cases presenting with firm swelling on physical exam, diagnostic imaging findings were consistent. These lesions were variably sized, expansile masses of mixed radiodensity, containing multiple discrete, irregular, and tooth-like opacities located at or near the alveolar margin (Figure 2). Within this group, three lesions had radiographic evidence of unerupted permanent dentition (cases # 6, # 7, and # 8) (Figure 3) and one lesion was associated with partial impaction (case # 2) (Figure 2). One lesion (case # 6) demonstrated dilaceration and rotation of the tooth adjacent to the odontoma, a well-demarcated fluid opacity, and extension of the lesion to the symphysis with mid-symphyseal deviation away from the lesion (Figure 4). One lesion (case # 3) had increased mineral opacity in addition to identifiable denticles, radiographically appearing as a combination of compound and complex odontoma. Tooth resorption was not associated with any odontoma in this study.

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Figure 2.

Odontoma in Case #2. Intraoral Radiograph Shows Discrete Denticles at the Distal Alveolar Margin of the Left Maxillary Canine Tooth (204), Resulting in Incomplete Eruption of the Canine Tooth.

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Figure 3.

Cone Beam Computed Tomography Images of an Odontoma in Case #8 at the Level of the Hyperattenuating Unerupted Right Maxillary Fourth Premolar (108). A) Transverse View of the Odontoma (Arrow). Denticles are Visualized at the Alveolar Margin Obstructing Eruption of Tooth 108. B) Dorsal View of the Odontoma Showing an Expansive Lesion with Hypoattenuating Rim Containing Discrete Tooth-Like Structures (Arrowhead).

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Figure 4.

Odontoma in Case #6. A) Photograph Showing a Firm Swelling with Intact Gingiva and no Visible Left Mandibular Canine Tooth (304). B) Intraoral Radiograph Demonstrating Discrete Radiopaque Structures and an Unerupted Left Mandibular Canine Tooth Crown (Arrow) within an Expansive Lesion Extending to the Symphysis Medially and the Left Mandibular Third Premolar (307) Distally. C) Cone Beam Computed Tomography (Sagittal View) of the Left Rostral Mandible Showing an Expansive Rostral Mandibular Lesion Characterized by Cortical Thinning, Central Area of Hypoattenuation Containing Small Irregular Hyperattenuating Structures and an Unerupted Canine Tooth Crown (Arrow).

In case # 1, radiographic signs included bilateral, well-circumscribed fluid opacities containing multiple discrete, round mineral opacities. The unilocular lesions were located ventral to the apices of the left and right mandibular first molars (309, 409), measuring 3 mm and 5 mm, respectively. Also noted radiographically was significant resorption of surrounding bone with mandibular ventral cortical thinning at the odontoma sites. No tooth displacement or eruption abnormalities were associated with these ventrally located odontomas. Radiographic incidental findings in case # 1 included missing teeth and generalized tooth resorption disease unrelated to the odontomas.

Radiolucent areas were present in seven lesions to variable degrees. Three lesions had radiolucent rims surrounding individual denticles (cases # 2, # 5, and # 8). One lesion had a radiolucent rim encircling an ossified odontoma (case # 3). Three lesions had unilocular radiolucent areas (cases # 1 and # 6), due to cyst formation. Case # 1 had four separate unilocular radiolucent areas, as described above. Case # 6 radiographically showed one unilocular radiolucent area containing denticles and the unerupted crown of the left mandibular canine tooth (304) (Figure 4).

CBCT was performed in addition to intraoral radiographs in three cases. Case #4 revealed alveolar bone lysis of the palatal aspect of the right maxillary fourth premolar (108), as well as alveolar bone expansion of the buccal aspect and denticles within the lesion. Case # 6 showed hypoattenuation secondary to suspected cyst formation, with visualization of the unerupted left mandibular canine crown (304) and multiple, distinct tooth-like structures (Figure 4). The Case # 8 CBCT study was consistent with the intraoral radiograph findings of an expansile, variably attenuating lesion with visualization of the hyperattenuating tooth-like structures on the buccal, palatal, and coronal aspects of the unerupted right maxillary fourth premolar (108), surrounded individually and collectively by hypoattenuating rims (Figure 3).

Treatment

Treatment options in this case series included either surgical enucleation/curettage or en bloc resection of the mass. Four of eight cases received en bloc excision (Figure 5) with 50% of those samples achieving complete surgical margins on histologic exam. The other four cases were treated by enucleation and curettage (Figure 1).

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Figure 5.

Odontoma in Case #5. A) Intraoral Radiograph of an Odontoma Located in the Mid-Body of the Left Mandible Causing Mesial Displacement of the Left Mandibular Fourth Premolar Tooth (308). B) Postoperative Intraoral Radiograph Following En Bloc Resection of the Odontoma.

Histopathology

Histologically, each of the nine lesions had discrete or coalescing denticles. While denticles were small and irregularly shaped, the dentin was uniform with normal organization of tubules (Figure 6). The denticles most often had crown formation and amorphous cementum bordered the root dentin. When the histologic section permitted evaluation of pulp cavities, both pulp stroma and the odontoblast layer were vital and typical of a normal tooth. Connective tissue that surrounded and supported the denticles resembled periodontal ligament with stellate stromal cells, fine fibrillar collagen, and infrequent foci of epithelium (resembling odontogenic rests). When odontogenic epithelium with basilar ameloblasts was represented in the histological section, this epithelium lined the enamel spaces along the crowns of the denticles. Of the cystic lesions, only samples from case # 1 had histologic evidence of an epithelial cyst lining. No inflammation was evident histologically in any case.

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Figure 6.

Odontoma from the Right Maxilla in Case #8. A) Photomicrograph Image of Irregular Denticles (Low Magnification). Bar = 1 mm. HE Stain. B) Photomicrograph of a Denticle with Enamel Matrix (E) within the Cleft that Separates Dentin (D) from an Attenuated Layer of Ameloblasts (Arrows) (High Magnification). Bar = 100 µm. HE Stain. C) Photomicrograph of a Denticle with Dentin (D) Bordered by a Layer of Predentin (Arrows) and Odontoblasts (O) (High Magnification). Bar = 100 µm. HE Stain.

Follow-up

Time to follow-up ranged from 1 week to 20 months postoperatively. Two cases were lost to follow-up. Of the six cases that had follow-up data, three had en bloc resection and three had enucleation. Case # 2 and case # 4 returned for 2-week post-surgical resection awake oral examination rechecks with normal results. Case # 8 returned 15 months post-enucleation for a routine annual examination with normal results on awake oral examination. Case # 6 returned 20 months after enucleation for an awake oral examination with normal results. Two cases reported updates via telephone call: a one-week post-enucleation update on case # 1 and a 20-month post-resection update on case # 7. No cases received anesthetized oral examination and imaging rechecks. No recurrence was evident in any of the cases with follow-up information at the time of writing, regardless of surgical treatment performed.

Discussion

This case series represents the first known publication of odontomas in cats and demonstrates the rarity of the condition in felines with only nine histologically diagnosed odontomas available over a 10-year period. Within this study, the incidence of odontomas in cats was 0.18% of all feline oral biopsies submitted. Furthermore, odontomas were 0.54% of all feline oral neoplasms diagnosed from those biopsy samples.

Similarly, odontomas are a rarely diagnosed odontogenic tumor in dogs. In dogs, odontogenic tumors have a documented incidence rate that is 0.49% of all oral tumors submitted for histopathology, depending on the study. ³ Yet in dogs under 1 year old, odontogenic tumors can constitute up to 65% of non-papilloma oral neoplasms.^6,7 Dog odontomas are a rarely occurring type of odontogenic tumor, with an incidence rate of 0.05% to 1% of all canine oral biopsy submissions.^3,8–10 Although the incidence of odontomas is similar for dogs and cats, multiple publications and case reports exist for dogs while they do not for cats.^{3,6,8,11–16}

In humans, odontogenic tumors are also rare with a reported frequency in a 2006 study of 1.2% of 1088 oral biopsy samples. ³ However, odontomas are considered the most commonly occurring odontogenic tumor in humans, constituting 75.9% of odontogenic tumors in the United States within the same study. ¹⁷ Odontomas in humans are well documented. ¹⁸

Odontomas are benign, intraosseous oral neoplasms comprised of mixed odontogenic germinal tissues, which can be locally destructive with no metastatic potential.^8,19 Odontomas are currently designated as hamartomas rather than neoplasia by the World Health Organization.^1,18,20,21 Neoplasms technically feature cell multiplication that is progressive and uncontrolled. ⁸ In contrast, hamartomas are considered developmental anomalies characterized by disorganized and malformed growths of normal cellular components native to the affected area.^8,20,22 In general, odontomas are considered to be mixed tumors initially induced by odontogenic epithelium, in a manner mirroring reciprocal induction during normal odontogenesis.^1,23 Odontomas originate from odontogenic epithelium and odontogenic mesenchyme, containing both hard and soft tissues. ²¹ Specifically, they are comprised of odontogenic epithelium, tissue derived from the dental follicle and dental papilla, and mineralized dental matrix as a result of odontogenic induction. ¹ Thus, enamel, dentin, pulp stroma, and cementum can be found within these lesions. ¹¹

Odontomas are categorized as compound and complex based on their degree of differentiation/organization of the various dental tissues. Compound odontomas, like those documented in this case series, are most common and characterized by discrete, tooth-like structures called denticles (Figure 1C).^2,13,14 In contrast, complex odontomas lack organized arrangement of the odontogenic germinal tissues, often with predominance of jumbled dentinal matrices.^1,2,13,20 The morphologic and histologic similarities observed in denticles compared to the normal tooth is due to odontomas having relatively normal odontogenesis. As a result, denticles have enamel, dentin with normal tubular arrangement, and pulp stroma arranged in a normal anatomical orientation to each other.^{2,11,13,15,18} Odontomas mature as the patient ages and have self-limiting growth potential. In its early phase, the odontoma often contains more odontogenic epithelium and soft tissue components compared to hard tissues. As the lesion matures, its composition shifts towards increasing amounts of hard dentinal matrix. ¹

The etiology of odontomas is unknown, although infection, heredity, genetic mutations, and trauma are possible contributors.^14,15,22,24 Due to their developmental-type origin, understanding of odontogenesis may provide some clues to their formation and pathogenesis. Rests of Malassez, which are remnants of the epithelial root sheath formed during embryogenesis, remain in the periodontal ligament and have been implicated in the development of odontogenic tumors.^{2,13,14,20,23} Furthermore, it has been hypothesized in the human literature that odontomas are a malformation developed during tooth formation, attributable to hyperactivity of the dental lamina, hyperdontia, and/or multiple schizodontia (splitting of teeth). ²⁵

Within this case series, there are similarities between humans, dogs, and cats in signalment trends, clinical signs reported, digital imaging findings, treatment options, and outcomes. Concerning signalment, odontomas are most commonly diagnosed in younger animals and younger humans, with no gender predilection noted.^1,18 In humans, odontomas are most common in children and young adults, with the most common age ranging between 10 and 19 years old. ²² Consistent with the young age found in dogs and humans, the median age at time of diagnosis of cats within this study was 14.5 months and no sex predilection was noted. Clinical signs in dogs include asymptomatic focal swelling of the maxilla or mandible, though larger maxillary odontomas are possible.^2,14 Other clinical signs documented in dogs include missing teeth, intraoral eruption of denticles, ocular signs of epiphora secondary to nasolacrimal duct obstruction, sneezing, and occasionally dysphagia and oral pain.^{8,11,13,15,26,27} In humans, odontomas are most often small in size and can be an incidental finding on imaging of an asymptomatic patient. ¹ If clinical symptoms are present, they are typically limited to that of missing teeth.^14,20,28 Like dogs, seven out of eight cats in this study were asymptomatic except for alveolar swelling seen on physical exam. Other common findings among humans, dogs, and cats included missing teeth in four cats and one cat having oral pain. Though case # 1 was not technically dysphagic as described occasionally in dogs, the presenting complaint of inappetence is a closely related clinical sign. The absence of alveolar swelling in case # 1 was more consistent with oral examination findings commonly seen in humans. No cats in this study had oculonasal signs. Lastly, the feline odontomas in this study showed lesion location evenly distributed, both in the rostro-caudal direction and in maxilla versus mandible. This is different from that seen in dogs and humans. Previous studies in dogs have shown an increased prevalence of odontomas in the mid-body to caudal mandible and to a lesser extent, the caudal maxilla.^3,11,12,15 However, more recent canine odontoma literature expands the location of odontoma formation to include the rostral maxilla, but not the rostral mandible.^6,8,14,26 In humans, compound odontomas are predominantly in the anterior jaw and complex odontomas appear usually in the posterior jaw.^22,29 In contrast to the dog and human literature, this study revealed no site predilection for odontomas in cats.

Diagnosis of odontomas involves digital imaging with histopathologic verification. In one human literature review of 160 odontoma cases, histopathology verified that 83.75% of odontomas were diagnosed correctly based on clinical examination and digital imaging alone. ²² Radiographic characteristics are well described in the literature and highly suggestive of odontomas, especially for the compound variant. Common findings include an osteolytic, expansile intraosseous mass of mixed radiodensity consisting of a mixed radiopaque center with a variably prominent radiolucent peripheral rim. Distinguishing features that are pathognomonic for compound odontomas include distinct, tooth-like opacities within the radiolucent area.^1,2,8,14,20 All cases included in this retrospective study were radiographically characterized by evidence of multiple distinct, radiodense tooth-like structures consistent with compound odontomas. However, the distinction between compound and complex odontomas can be ambiguous at times due to the presence of both characteristics within the same lesion. ¹ In this study, one case in particular (case # 3) demonstrated increased matrix mineralization, radiographically obscuring the denticles due to summation. In this case, the age of the patient upon discovery of the lesion (7 years old) could be a major contributing factor, giving the lesion ample time to reach full maturation and fusion of denticles by cemento-osseous tissue.

In total, three cases showed radiographic evidence of unerupted teeth associated with the odontoma and one of these was cystic (case # 6). Cyst formation, if present along with an odontoma, can either originate as a dentigerous cyst in association with an unerupted tooth or result from accumulation of interstitial fluid in a space lined by odontogenic epithelium that is part of the odontoma.^6,8,14 Within this case series, two cases (cases # 1 and # 6) had radiographic evidence of cyst formation characterized by unilocular radiolucencies encompassing the mineralized radiopaque structures. A third case (case # 3) had a more prominent radiolucent border encircling the odontoma which clinically and histologically was characterized as cystic fluid.

Two odontomas displaced adjacent teeth in this study, similar to occurrences in dogs and humans.^1,29,30 Tooth root resorption was noted in case # 1, similar to what has been reported in humans.^22,30 Although root resorption was found in the area of the odontoma in case # 1, it was also present in multiple other locations throughout the mouth. It is suspected that the tooth resorption of the odontoma-associated teeth was secondary to idiopathic, generalized tooth resorption disease rather than caused by the odontomas in case # 1.

CBCT assisted in evaluation of the extent of the lesion in three cases. The CBCT study of the ossified mass of case # 6 clearly highlighted the extent of cyst formation, eliminating the summation found in intraoral radiographs that can obscure interpretation (Figure 4). CBCT revealed the palatal extent of the odontoma and lytic changes of the caudal maxilla in cases # 4 and # 8 (Figure 3). CBCT or conventional CT offers an advantage over intraoral radiography for large lesions that exceed the size of the radiographic film and CT provides more complete evaluation of a three-dimensional lesion. ⁶ Given that the odontomas in this study were limited in size by the smaller size of the feline patient, most lesions could be fully viewed on one intraoral radiograph. Nevertheless, CBCT (if available) could provide additional information for lesions located in the caudal mandible where dental imaging is difficult to obtain and for lesions that extend beyond the size of a radiographic plate. Lastly, CBCT can provide information on a lesion's 3D characteristics.

Differential diagnoses based on physical and radiographic examinations include calcifying epithelial odontogenic tumors, amyloid-producing ameloblastoma, sclerosing osteomyelitis, osteoma, ameloblastic fibro-odontoma, ossifying fibroma, periapical cemental dysplasia, and dentigerous cyst.^8,11 The presence of tooth-like structures narrows the field substantially to a presumptive diagnosis of compound odontoma or ameloblastic fibro-odontoma. Ameloblastoma fibro-odontoma (also known as feline inductive odontogenic tumor) is a particularly important differential diagnosis since these tumors occur in young cats and may contain dental matrix that resembles complex odontomas. ³¹ Histopathology is essential to confirm the diagnosis and rule out other types of odontogenic tumors. Biopsy submissions to a pathologist who has a focus on oral and maxillofacial pathology is recommended.

Treatment recommendations for odontomas are either by en bloc surgical excision or enucleation and curettage. Literature for both dogs and humans demonstrates excellent prognoses with rarely reported recurrence for either treatment option.^8,32 In one study, three dogs had aggressive surgical excisions of odontomas. Two of these cases had wide resections performed due to tumor size equal to or exceeding 4 cm in size. The third case in that study had recurrence after initial incomplete curettage of the lesion, leading to a more aggressive en bloc resection surgery. ²⁶ In the current feline case series, no evidence of recurrence was reported, regardless of treatment modality.

Limitations of this study include its retrospective design spanning 10 years, which limited medical record acquisition and follow-up data. Variables existed in case management, surgical approach, and availability of histopathology results due to the retrospective nature, limiting the number of cases that met the inclusion criteria. Due to the near pathognomonic diagnosis for compound odontoma that digital imaging provides, veterinarians or owners may decline histopathological submission of lesions. If this is so, the incidence of odontomas in cats could be higher than shown in this study. Thirdly, the absence of digital imaging for recheck evaluation limits the ability to fully evaluate recurrence rate. Given that some odontomas can appear as incidental findings without visible signs of swelling, such as in case # 1, the lack of intraoral radiograph or CBCT rechecks of the previous odontoma site presents the possibility that lesions could recur without detection. Lastly, the small number of patients qualified for inclusion in this study was also a limitation in data analysis.

In summary, odontoma is an important differential diagnosis for felines presenting with focal alveolar swelling. Furthermore, this study underscores the importance of digital imaging in the diagnosis of any intraosseous lesion including odontomas. Lastly, intraoral radiographs and CBCT are highly suggestive of a diagnosis for compound odontomas, but histopathology is necessary to confirm the diagnosis.